Table of Contents
Anatomy | Drawings | Histology | Mesothelial cells | Connective tissue cells | Black spotsCite this page: Avadhani V. Anatomy & histology. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleurahistology.html. Accessed June 1st, 2023.
Anatomy
- Lungs are surrounded by visceral pleural, a delicate serous membrane arranged as a closed invaginated sac
- Inner chest cavity is lined by parietal pleural membrane
- Visceral and parietal pleura define the pleural space / cavity, which normally has minimal volume, unless lungs collapse or air / fluid collects between the two layers
- Only minimal contact between right and left pleural sacs
- Regional lymph nodes are internal mammary, intrathoracic, scalene and supraclavicular
Histology
- Lined by mesothelial cells overlying vascularized connective tissue
- Mesothelium provides smooth, low friction surface to facilitate the gliding motion of lungs in pleural cavity, heart in pericardial cavity, viscera in abdominal cavity
- Gliding facilitated by numerous surface microvilli, thick glycocalyx, secretion of hyaluronic acid and other glycosaminoglycans
Mesothelial cells
Microscopic (histologic) description
Positive stains
Electron microscopy description
- Monolayer of flat or low cuboidal cells with bland and uniform nuclei, fine delicate chromatin, inconspicuous nucleoli
- In fine needle aspirates, have well defined cytoplasm and distinct cell borders
Positive stains
Electron microscopy description
- Apical tight junctions, desmosomes, surface microvilli, cytoplasmic tonofilaments in bundles
Connective tissue cells
Black spots
- Carbonaceous / anthracotic pigments in parietal pleura
- Present in > 90% of urban dwellers in Belgium at autopsy
- Not related to hyaline pleural plaques (Am J Surg Pathol 2002;26:1198)
- Associated with lymphatic drainage
- Micro description: deposits of opaque particles (intra or extracellular) of various sizes under an intact mesothelial layer, associated with chronic inflammatory cells